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Article Citation - WoS: 15Metal-Salt Enhanced Grafting of Vinylpyridine and Vinylimidazole Monomer Combinations in Radiation Grafted Membranes for High-Temperature PEM Fuel Cells(Amer Chemical Soc, 2020) Mojarrad, Naeimeh Rajabalizadeh; Sadeghi, Sahl; Kaplan, Begum Yarar; Guler, Enver; Gursel, Selmiye AlkanProton exchange membranes were prepared and characterized for utilization in high-temperature proton exchange membrane fuel cells, HT-PEMFCs. 1-vinylimidazole (1-VIm) and 4-vinylpyridine (4VP) monomers were simultaneously grafted onto pre-irradiated ETFE (ethylene-co-tetrafluoroethylene) films which were prepared using gamma-rays with a dose of 100 kGy, as a robust substrate to prepare acid-base composite membranes. The grafting reaction was performed at 60 degrees C for 24 h followed by protonation via phosphoric acid doping in the subsequent step. The effect of adding ferrous salts as promoters in grafting was investigated by characterization of resultant membranes via thermal gravimetric analysis and mechanical tests. The fuel cell tests were conducted under different relative humidities (RHs) and applied temperatures. Membranes prepared with salt addition exhibited superior proton conductivities. Results including up to 80 mS cm(-1) conductivity at 110 degrees C in 60% RH and excellent thermal stability, even at 300 degrees C, suggest these membranes are promising for HT-PEMFC applications.Article Citation - WoS: 7Citation - Scopus: 9Development and Performance Analysis of Polybenzimidazole/Boron Nitride Composite Membranes for High-Temperature Pem Fuel Cells(Wiley, 2022) Hussin, Dedar Emad; Budak, Yagmur; Devrim, YilserIn this research, polybenzimidazole/boron nitride (PBI/BN) based composite membranes have been prepared for high-temperature PEM fuel cell (HT-PEMFC). BN was preferred because of its superior thermal robustness, high chemical stability, non-conductor property, and high plasticizer characteristic. The loading of BN in the composite membrane was studied between 2.5 to 10 wt%. The composite membranes were characterized using TGA, DSC, XRD, SEM, mechanical tests, acid doping/leaching, and proton conductivity measurements. The highest conductivity of 0.260 S/cm was found for PBI/BN-2.5 membrane at 180 degrees C. It has been determined that the PBI/BN-2.5 membrane has higher performance than the PBI membrane according to the HT-PEMFC tests performed with Hydrogen and dry air. The heightened HT-PEMFC performance can be ascribed to interactive effects between BN particles and the PBI polymer matrix. PBI/BN composite membranes show a good perspective in the high-temperature PEMFC applications.
